1. The Field of the Invention
This invention relates to a tool move control method and a tool move control apparatus wherein a tool can be smoothly moved without interfering with a workpiece and a tail stock in a numerically controlled lathe, when the tool is rapidly moved.
2. Description of the Prior Art
Heretofore, in order to move a tool without interfering with a workpiece and a tail stock when the tool is rapidly moved, such as when a machining on the tool is started, at machining operation, or when the machining is finished, as shown for example in FIG. 8, a relay point VP is set in a machining program between a start point SP and an approach point AP with respect to a workpiece 16. Tool 1 is controlled to move via the relay point VP.
There is known another method wherein a tool is automatically moved between the approach point AP and the relay point VP, while the tool is manually moved by an operator between the relay point VP and the start point SP.
However, in the case of the former, a programmer is required to instruct all travelling paths of the tool from the start point to the approach point in the machining program. Thus, preparation work of the machining program becomes complicated. In addition, there remains a risk of a programming error which requires a complete prior check. In the case of the latter, every time the tool is rapidly moved, the operator is required a manual operation. This results in a greater work load for the operator. In addition, manual operation is against modern trends which perform machining using automation.
Further, in recent years, various kinds of barrier functions and stroke limit functions have been employed and added to the conventional device in order to prevent a tool from entering into a certain area. However, such functions intend to merely prohibit the entry of a tool and stop the action of working at that time. They do not intend to move a tool in a manner which avoids an interfering subject.